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Where To Put Brake Fluid: Changing, Maintaining + More

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Knowing where to put brake fluid is key in topping up your supply, understanding when to change it out entirely, and ensuring your braking system remains safe.

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  • Where To Put Brake Fluid: Changing, Maintaining + More

Brake fluid is an essential part of your car's braking system. If the levels are too low, your brakes may become less responsive or stop working altogether. That's because this fluid is key in maintaining healthy brakes, discs, and pads.

When you press the brake pedal, hydraulic fluid is pushed down to activate your brake pads. As well as keeping the brakes functioning, this fluid is also a lubricant with anti-corrosive properties. That helps keep all the moving parts smooth and effective.

Even still, brake fluid doesn't last forever. You need to top it up regularly, and then have it changed altogether every two years. A skilled mechanic can help with the full change-out, but adding brake fluid periodically can be done by yourself at home.

However, many new drivers are uncertain on where to put brake fluid. Despite being an essential part of your car's braking system, the placement of the fluid's storage container isn't intuitive.

How To Top Up Brake Fluid

To keep your car in peak condition, let's explore where you should put your brake fluid, how to gauge the right amount when topping up the supply, and when it's time to undergo a full change:

1. Locate Your Master Cylinder

The storage container for your brake fluid is located on top of your master cylinder. You can find its location by reading your vehicle's handbook, which should provide written instructions and a diagram.

In any case, the master cylinder is located under the bonnet, usually on the driver's side of the vehicle, and towards the back of the engine compartment.

  • You should see a metal cylinder with a plastic container on top - this is the brake fluid reservoir.
  • In most cases, the cap itself will indicate you're in the right place, inscribed with "brake fluid."
  • Here, you will discover a "full" line and a "minimum" line, which determines how much fluid is present and how much should be added.
  • In modern cars, you may be able to see the fluid level from the outside.

Keep in mind : if you're not parked on a flat surface, your reading is likely to be inaccurate.

2. Purchase The Right Brake Fluid For Your Car

The cap of the brake fluid reservoir will usually tell you the kind of brake fluid that's needed. This will be one of the following:

  • DOT3
  • DOT4
  • DOT5

If you can't find it here, you can also look it up in your vehicle handbook. Once you've picked the right kind, you will have a choice between standard and premium fluid.

Premium brake fluids offer bonus additives and oils, but unless you are driving your car on the track, standard, fresh fluid is all you need to keep your system running at optimum levels.

Brake fluid has just a two-year lifespan when unopened. Bear this in mind when you purchase. As a general rule, don't buy in bulk.

3. Pour In The Brake Fluid

Now for the easiest part:

  • Open the cap
  • Pour the brake fluid in until it reaches the "maximum" line
  • Screw the cap back on securely
  • Shut your bonnet
  • You're ready to go

4. Maintain Your Brake Fluid

Since brake fluid is such a vital component to your braking system, you should ideally check the levels once a week.

If you notice the levels are unusually low each time, you may have a leak. At this stage, book an appointment at your local garage as soon as you can. Leaking brake fluid is not only costly to replace, but could leave your car without functioning brakes at a poor time.

5. Have Your Brake Fluid Changed Every Two Years

Water naturally enters your brake fluid over time, due to weather changes or exposure to rain. The more water that reaches it, the more diluted your brake fluid becomes. This then lowers the temperature at which the fluid boils, which can result in your brakes becoming less responsive and even failing to stop your car.

As a result, manufacturers recommend changing out your brake fluid entirely every two years. This process involves "bleeding" your brakes to remove the old fluid and make room for the system to be refilled. This also gets rid of any bubbles or vapour that may be lodged in it. Specialist equipment is needed to do this properly.

If you choose Autofusion for this service, our technicians will drain the old fluid in your brakes and then refill them with new fluid, in line with the correct specifications. We will then dispose of the old fluid in an environmentally friendly and safe way.

Included in the package is a test of your braking system to ensure it is functioning at peak capacity. To complete the service, we record the fluid change in your service book.

How Does Brake Fluid Work?

Brake fluid not only amplifies your car's braking force, but it also acts as a lubricant to prevent corrosion in moving parts of your brakes.

But how does brake fluid work, and why are there no alternatives?

The Braking System

When you press down on your brake pedal, the pistons inside the master cylinder (which lives within the engine compartment) compress to allow the brake fluid to travel under pressure. The compression from the pistons increases the pressure within the brake lines, which is where the pressurised brake fluid is contained.

The brake lines divert the force of your pedal into the front and rear brakes of your car, using this pressurised brake fluid. The brake fluid then converts the energy used on the pedal into braking force against the pads, which squeeze the brake rotors. This leads the rotors to slow down and eventually bring them to a halt.

Why Does Brake Fluid Deteriorate?

Brake fluid doesn't last forever. Over time, it soaks up water from the hoses, joints, and pipes that it lubricates. As the water content in the fluid rises, the temperature at which it boils will fall. In turn, this can make your braking system less effective.

As water builds up in the hydraulic fluid, your brakes will become less responsive, making it harder to slow or stop your car. You may first notice this as a spongy feeling when you push on the brake pedal. If this goes on long-term, your brakes may fail completely. That presents a very real danger on the road.

If your brake lights come on, be sure to act quickly. Reaching out to the experts at your local Autofusion can help repair any issues, reset the brake light, and ensure you're safe on the road.